Description du contenu de l'enseignement
The course draws on the basics of Ray Optics (which are introduced within the Common Curriculum – see ‘Fundamentals of Optics’ course) in the framework of the Gaussian (paraxial) approximation to further explore issues related to optical system design and performance analysis. Concepts of aperture stop (pupil) and field stop are presented and used to analyse the performance (resolution, field of view, depth of field) of optical systems made up of a combination of several lenses and/or mirrors.
Modalités d'organisation et de suivi
Part I: Ray transfer matrix formalism
The aim of this part is to introduce the ray transfer matrix formalism (in the framework of the Gaussian (paraxial) approximation) and to use this powerful tool to:
- give a simple demonstration of the usual conjugation and magnification formulae (for curved refractive surfaces, curved mirrors, thin lenses);
- give a rigorous description of centred optical systems in general, by defining their cardinal elements and deriving the generalized conjugation and magnification formulae.
Part II: Optical instruments – Properties and performance (Case studies)
- Purely refractive systems (centred lens combinations): Astronomical and terrestrial telescopes, Lyot's coronagraph, Microscope, Gauss's objective…
- Two-mirror systems: Schwarzschild's objective, Cassegrain's telescope, Gregory's telescope…
- Catadioptric systems (combinations of lenses and mirrors): Telephoto lens…
Part III: Introduction to geometric and chromatic aberrations
This part gives a short introduction to the consequences of glass dispersion and deviation from the Gaussian (paraxial) approximation conditions – namely, chromatic and geometric aberrations. It will mainly be addressed during the practical work session (4hrs) with the optical design software Code V.
Compétences à acquérir
After completing the course, the student will be able to:
- identify the conditions of validity for the Gaussian (paraxial) approximation;
- describe the propagation of an optical ray through an imaging system using the ray transfer matrix analysis;
- describe the properties and evaluate the performance of imaging optical systems in the framework of Gaussian (paraxial) optics;
- identify the geometric aberrations that can reduce the performance of an imaging system as soon as the Gaussian approximation is not satisfied;
- explain why and how the combination of two lenses made with different glasses can reduce the chromatic aberrations.
- Basics of Ray Optics (see ‘Fundamentals of Optics’ course in the Common Curriculum).